SE420750B - SOUND-INSULATING BUILDING ELEMENT WITH GREAT STUFF - Google Patents

Description

1811891-6 as low as possible, preferably below 250 Hz, preferably below 100 Hz. A major disadvantage of a sonically well-functioning double wall of known construction is that rigidity and mechanical bearing capacity become very small in relation to the total thickness of the construction and often less than the rigidity of a solid equally heavy single board.

If the air gap in the construction with double discs is replaced by a light but rigid material with which the discs are connected, e.g. by gluing, the rigidity and bearing capacity are radically increased, but at the same time the sound insulation decreases, since the construction acoustically functions almost like a single board, and only the mass determines the sound insulation. The invention relates to a building element which combines high rigidity and load-bearing capacity with good airborne sound insulation capacity. A sound-insulating building element according to the invention is characterized by a first inner surface element of rigid material with inner cavities, a second inner surface element which is disc-shaped, thin and air-permeable and is connected to one of the two main surfaces of the first inner surface element, a third surface element connected with the second main surface of the first inner surface element, the second and third elements having an E-module greater than 109, and a fourth outer, dense surface element arranged parallel to and at a small distance from the second inner surface element in such a way that substantially the whole the fourth element can oscillate substantially freely relative to the second inner element. In the building element according to the invention, the first internal element and the elements connected to it on both sides with a high E-module form a base element with great rigidity, whereby the entire building element obtains the desired bearing capacity and rigidity. The first inner element can consist of a mineral wool board with the main part of the fibers extending substantially perpendicular to the plane of the building element, but it can also consist of foam or light plastic with communicating pores, e.g. polyurethane foam plastic, or of a board with a honeycomb-like structure.

The cavities in the first inner element, the total volume of which is suitably at least 90% of the total volume of the element, must communicate with the air passages in the air-permeable element, whereby the air in said cavities is used for the sound-damping function of the building element. The air in the cavities is represented in the mechanical oscillating circuit which the building element according to the invention corresponds to by a spring connected in series with the spring represented by the air in the gap between the air-permeable element and the outer, tight element. This gap may be relatively narrow, generally not more than 10 mm, preferably not more than 5 mm.

The outer tight element can be connected to the air-permeable element by means of rigid or soft spacers at at a large distance from each other connecting points with a small total area in relation to the total surface of the building element. The connection can be made pointwise or linearly.

Between the connection points, the gap may be empty or occupy a soft, porous air-permeable material, e.g. foam plastic with open pores. In the latter case, e.g. the risk of direct contact between the outer element and the air-permeable element, for example when exposed to external pressure. It is also possible, instead of by means of spacers with a small area relative to the total surface of the building element, to connect the outer tight element to the air-permeable element only by means of a thin layer of a porous soft air-permeable material, e.g. soft foam with open or communicating pores.

The invention is described in more detail below with reference to the accompanying drawing, in which Figs. 1-3 represent known building elements and Fig. 4 represents an embodiment of the building element according to the invention.

Fig. 1 shows a known element consisting of a thin single disc 1 which is dense, i.e. lacks continuous air passages in large numbers. The system is usually called a light single wall. In relation to the sound P1 incoming on one side of the element, the sound P2 emanating from the other side is only slightly lower, ie. the sound insulation capacity of the element is low or moderate. A mechanical oscillation system corresponding to the element essentially comprises only one mass, corresponding to the weight of the disc per unit area.

Fig. 2 shows a system with two tight discs 1 and 2 arranged at mutual intervals 3, in which air is trapped. This system corresponds to a mechanical oscillating circuit with two masses interconnected by a soft spring, which the air trapped between the discs represents. This double wall element has a high sound insulation capacity in relation to the single wall according to Fig. 1, ie. P3 significantly less than P1, at frequencies above the fundamental resonant frequency of the system. However, the rigidity and bearing capacity of the element are unsatisfactory for many applications. An improvement in the latter respect can be achieved by the construction according to Fig. 3, in which the air gap 3 is replaced by a rigid, relatively thick foam sheet 4 on whose side surfaces dense, thin sheets 1 and 2 are glued. The system thus obtained corresponds to an oscillation system consisting of two masses connected by a parallel connection of two springs, one of which is represented by the air content in the foam sheet 4 and the other is represented by the foam material in the sheet itself. However, the improvement in rigidity and bearing capacity is associated with a deterioration of the construction's sound insulation capacity, ie. P4 is not substantially smaller than P1, and this is because the composite structure will actually behave substantially as a rigid single plate.

Fig. 4 shows in one embodiment a representative section of a building element embodied according to the invention which combines great rigidity and load-bearing capacity with great airborne sound insulation capacity. The construction comprises a first inner element 10 with inner cavities. The element may consist of mineral wool, suitably with fibers perpendicular to the plane of the plate, rigid porous plastic with communicating inner pores, e.g. polyurethane foam plastic, a honeycomb construction or the like. at one side of the element a dense disc 2 is glued, while a disc 5 with a large number of suitably evenly distributed perforations 6 is glued to the opposite side of the element 10.

By means of spacers 9, a thin, dense outer plate 7 is attached to the plate 5 with a small gap 8 which can amount to one or a few mm. The spacers 9 can be point-shaped and suitably evenly distributed along the surface of the wall element, but they can also be designed in another way, e.g. consist of narrow elongated members that form connecting zones at large mutual intervals. The connection between the spacers 9 and the plates 5 and 7 can take place, for example, by gluing.

The mechanical oscillating circuit corresponding to the building element according to Fig. 4 comprises the two masses corresponding to the discs 2 and 7 interconnected by a series connection of a first spring corresponding to the air in the gap 8 and a second spring corresponding to the air in the inner element 10, the cavities or pores communicates with column 8. d 7811891-6 The system's fundamental resonant frequency becomes low and the sound insulation becomes good, ie. P4 is much smaller than P1, within a large frequency range.

If the disc 5 had been tight, only the narrow gap 8 would have determined the fundamental resonance frequency, which would then have become much higher.

Regarding the air-permeable sheet 5, it should be said that it. although shown in Fig. 4 as a sheet metal plate, may have different alternative embodiments according to the present claims. It can e.g. consist of plastic, in particular reinforced plastic, a metal wire mesh, etc.

For both element 2 and element 5 it applies that the E-module (in the plane of the element) should be at least l09N / m2, suitably at least l0l0N / m2 and preferably at least 2 x 1010N / m2.

The thickness of the constituent layers can be within the limits stated below, whereby for the elements 2, 5 and 7 it has been assumed that the material is sheet metal.

Element 2: 0.5-5 mm, preferably 1-2 mm "- 5: 0.5-5 mm, preferably 1-2 mm" - 7: 0.5-5 mm, preferably 2-4 mm "- 10 : 20-150 mm, preferably 25-100 mm If lighter materials than metal are used for elements 2, 5 and 7. Larger thicknesses can be chosen, especially the outer element 7 for which many different materials can be used. consists of a plastic sheet, a chipboard, a plasterboard, etc.

The construction shown in Fig. 4 is asymmetrical, i.e. the two halves on either side of an imaginary plane 11 in the inner element 10 are mutually fundamentally different. A symmetrical structure, ie. however, a building element consisting of two contiguous halves interconnected in a central plane II, each in principle equal to the element half shown to the left of the plane II in Fig. 4, may, however, be preferable for certain applications.

Claims (10)

7811891-6 PATENT REQUIREMENTS 1. Sound-insulating building elements comprising a plurality of flat elements arranged next to each other, characterized by degreasing -. first inner surface element (10) of rigid material with inner cavities, a second inner surface element (5) which is disc-shaped, thin and air-permeable and is connected to one of the two main surfaces of the first inner surface element, a third surface element (2) connected to the second main surface element of the first inner surface element, the second and third elements having an E-module larger than 109, and a fourth outer, dense surface element (7) arranged parallel to and at a small distance from the second inner surface element in such a manner that substantially the entire fourth element can pivot substantially freely relative to the second inner element (5). Ä Element according to claim 1, characterized in that the third surface element is substantially dense. Element according to claim 1, characterized in that the third surface element is substantially air-permeable. Element according to claim 3, characterized by a fifth surface element which is dense and arranged parallel to and at a small distance from the third surface element in such a way that it can swing substantially freely in relation to the third surface element 5. An element according to any one of the preceding claims, characterized in that the first inner element consists essentially of a minor wool sheet with transverse fibers. Element according to any one of claims 1-4, characterized in that the first inner element consists essentially of a rigid, porous material with communicating pores, e.g. foam plastic, preferably polyurethane foam plastic, or a honeycomb construction. Element according to one of the preceding claims, characterized in that the second inner element consists of a rigid disc with a large number of evenly distributed perforations. Element according to one of the preceding claims, characterized in that the outer surface element is connected to the second inner element by means of rigid or soft spacers at spacing connecting points with a small area in relation to the total surface of the element. . Element according to any one of claims 1-7, in that the outer surface element is connected to the second inner element essentially only by means of a thin layer of soft, porous known material, for example foam plastic. 10. An element according to claim 8, characterized in that a soft, porous material, for example foam plastic, is arranged in the space between the spacers.